Joining the ranks of 5 countries other than the U.S. that have hit the 1 gigawatt solar milestone (Germany, Italy, Spain, Japan, and the Czech Republic), California has now installed its 1st gigawatt (or 1,000th megawatt) of rooftop solar installed.

To put that into perspective, 1GW of solar can power up to 750,000 homes and is equal to about 2 coal-fired power plants.

“California can become the Saudi Arabia of the sun if it continues to get behind big, successful solar programs,” said Michelle Kinman of Environment California and co-author of “Building a Brighter Future: California’s Progress Toward a Million Solar Roofs.”

TheCalifornia Solar Initiative was reported as a key driver of growth, helping to bring 600 megawatts online. And falling solar prices combined with solar leases for as little as $0 down have been a tremendous growth driver as well.

205 MW of the 1,000 MW installed were installed in 2011, despite the sagging economy.